Improvement in steamt-eng-ine slide-valves



i of' similar size as those ouA the valve-seat, which pass stant communication is maintained between each steamport and the corresponding' ports in the covering, and a perfect equality of pressure is thus obtained on all sides.

G G, w, i amiga ,time met @Bt-im. s

wwaeesaww- Letters Patent No. 85,105, dated December 22, '1868.

IMPROVEMENT IN STEAM-ENGINE SLIDE-VALVES.

The Schedule referred tuin these Letters Patent and making 'part of the same.

To all whom it ma/y' concern.

Be it known that I, JOAH LAWSON, of Allegheny City, in the county. of Allegheny, Aand State of Pennsylvania, have invented certain new and useful Improvements in a Balanced Steam SlideValve; and Iv do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part .of this speciticaf tion.

The nature'of my invention consists` in providing a covering or false chest, which is suppo1ted,.in a suitable manner, on the'valve-seat of an ordinary steamcylinder, and so arranged as to form an oblong or square box;y in which the valve is reciprocated. Thew surfaces that touch the Valve are made steam-tight, in any suitable manner. i l

Opposite each port on the valve-seat, the beforementioned covering is provided with ports or recesses,

through and over the covering; By this means, con- By also constructing the valve of i any suitable shape, of only one-half the width or length of the steam-ports, and also making an opening or passage through it.

To enable others skilled in the art to make-and to use my invention, I Will describe its construction and operation.

In the accompanying -drawings- Figure l is a perspective view of valve 'and covering, showing arrangement of ports.

Figure 2, a transverse section of the same; Figure 3, a plan'ofvalve-seat on cylinder.- A represents the upper valve-seat. A, the right-hand induction-port. A2, the left-hand induction-port. A3,-the eduction-port. B, the covering B2', the right-hand false induction-port. B2, the left-hand false induction-port. B3, the false eduction-port. O, the valve'. Of, the passage through. "D, the cylinder-valve seat.

E3, the right-hand main induction-port. E2, the left-hand main induction-port. E3, the main eductiou-port. -The mode of operating my devices` is as follows, viz:

steamorinduction-ports Al A2,

Steam being admitted into the steam-chest, in any ordinary manner, .the valve O being in the position as steam will then return through the opening, 0'-, of the valve 0,' and' through the ports A3 and B3 to the eduction-pipe.

The, advantages I claim in my invention are the reduction of the' areav of the valve, consequently diminishing friction, and, as a constant communication of 'steam is kept up all through the several passages, thus keeping the valve, as it were, in equilibrium; and, since "the slide-'valve C, with its central opening, C', establishes the communication between the exhaust or eduction A3 and E3 and its corresponding port B3 in the cov-- ering, B, and in any position in which the valve C; un-

covers a port, whollyor partly, the 4corresponding port in the covering, B, isacted upon precisely *in a similar manner. The pressure, therefore, uponk all partsfof the l Valve C is equally balanced.

My invention is also peculiarly adapted for steamhammers, or to any valve-m ovement effected by manual power, since, the valve 'being perfectly balanced, it re quires but little exertion to cause it to reciprocate.

My improvement can be easily adapted to existing steam-cylinders, since it requires but little change'in the details.

Having thus described the construction .and operation of my improvements in balance-valves,

Whatl claim, and desire .to secure by Letters Pate ent isL- 1. Thecovering, B, over the slide-valve C, with and. corresponding ports BI B2, and eductioneports -A3 and B3 passing through and over thesame, constructed substantially. as described.

2. The construction of the slide-valve G, with its cen-.

trai opening-or passage G', substantially as described. 3. The combination and arrangement of the covering, B, With its ports Al A2 A3 and B B2 BS, with the valve C and its opening, Gf, when constructed and ar- 'ranged as herein described and set forth.

In testimony that I claim the foregoing as my own, I aiiX my signature, in presence .of two Witnesses.

' J OAH LAWSON.

Witnesses:

PnncEvAL Bnolmr'r, -.Torna 1P. CLARK'. 

